What is the minimum connection interval for multilink central with 4 periphera?l

Question

Hello,I found in S120 documentation that minimum connection interval for 8 peripheral connected to central must to have minimum connection interval 20 ms.But what is the minimum connection interval for 4 peripheral?It is posible that 4 peripheral send data at 4 kbytes/second and central to receive all at the same time withowt lose the packet?In datasheet write that data rate is 4 kbyte/second,but I don't understand if 4 kbytes from all peripheral or from each peripheral?
Thanks in advance!

Petter Myhre · Accepted Answer

The minimum recommended connetion interval for eight connections is 20 ms. This is because the time needed between radio events is 2250 us. See Table 25 in the S120 SoftDevice specification v2.1. So 8*2250 us = 18 ms, which rounds up to 20 ms. More information can be found in Section 11. 
 Four connections would give 4*2250 us = 9 ms, so in my head a 10 ms connection interval should work (maybe a bit more). This needs to be tested though. 
 I'm not sure where you get 4 kbyte/second from. Normally the S120 is a client and the peripheral device sends notifications as a server. In Section 13 in the spec it says the as a client and with a 20 ms connection interval can achieve a throughput of 8 kbps if it is receiving notifications, per connection (stated above the table). This is kilobitpersecond, so in Bytes it is 1 kB/s. 
 If a connection interval of 10 ms works, should be able to achieve 16 kbps, or 2kB/s, per connection. 
 PS. You will not lose any packets, you can see a decrease in throughput, and in worst case you will have link loss.